As system administrator of my home network, it worries me that a device on my network might be involved in an attack like this, and I would never know.

Maybe the target of such an attack could gather a list of IP addresses used in the attack, then pass them to Google, who might warn on their search homepage if you browse from one of the IPs on the list? (e.g. "Some of your internet devices may be at risk, click here to find out more") I know IP addresses are a poor proxy for identity, but it could be a step in the right direction.